1. Field of the Invention
The present invention relates to a method of repairing broken lines and, more particularly, to a method of repairing LCD data lines.
2. Description of the Related Art
Liquid crystal display(LCD) devices are a well-known form of flat panel displays with advantages of low power consumption, lightweight, thin profile, and low driving voltage. The liquid crystal molecules change their orientations when an electronic field is applied. In the display region of the LCD, an array of pixel regions is patterned by horizontally extended gate lines and vertically extended data lines. Each pixel region has a thin film transistor (TFT) and a pixel electrode. The TFT serves as a switching device.
As described above, the TFT array substrate has wiring patterns such as the gate lines and data lines, that supply image signals to drive the pixel electrodes. However, the wiring patterns may easily disconnect if the regions they pass are not smooth or during the heat treatments or etching processes, resulting in open or short circuits. As size and resolution of LCD device continue to increase, large numbers of data lines and gate lines with a narrower line width are required on the TFT array substrate. The fabricating difficulties are also increased, causing a greater possibility of broken wiring patterns. Accordingly, it is desirable to provide a repair method that allows the LCD to operate despite broken wiring.
FIG. 1 is a top view showing a conventional method of repairing the disconnected data lines. On a TFT array substrate 10 of an LCD, a display region 20 has a plurality of horizontally extended gate lines 12 and a plurality of vertically extended data lines 16 to form an array of rectangular pixel regions 22. The TFT array substrate 10 also includes a plurality of gate pads 14 at an end of each gate line 12, and a plurality of data pads 18 at an end of each data line 16. In addition, a plurality of repair lines 24A, 24B and 24C are formed to cross the data lines 16 outside the display region 20.
For example, when a broken point A interrupts the image signals passing through the broken data line 16A, laser fusing or other conventional techniques can be used to connect points 26a and 26b where the broken data line 16A meet the repair line 24A, and the repair line 24A is cut off at positions 28a and 28b. Therefore, image signals can go through the repair line 24A to reach the broken point A. However, a capacitor is existed between the repair line 24A and the data line 16A, the image signals will be distorted at the intersecting point 26a or 26b when passing through the repair line 24A. Particularly, as the number of data lines 16 increases, the number of the intersecting points also increase, and thus the increased capacitors worsen the signal quality. Moreover, depending on the location of the broken data line, a large delay may be incurred due to the resistance and capacitance of the repair line between opposite ends of the broken data line. This increased delay may be unacceptable for large, high-resolution LCD devices. In addition, a single data line is generally repaired using a single repair line and the number of repair lines 24 is limited due to the size of the display region 20. Therefore, a method of repairing the broken data lines without fabricating repair lines to solve the aforementioned problems is called for.
The present invention provides a method of repairing broken data lines without fabricating extra wiring patterns outside the display region. The repairing method forms a repair line vertically across pixel regions.
On a flat display panel, a substrate has a first pixel region and a second pixel region formed by a first data line and a second data line extending vertically, and a first gate line and a second gate line extending horizontally. A first pixel electrode and a second pixel electrode are formed in the first pixel region and the second region respectively. An opening is formed between a first broken point and a second broken point of the first data line in the second pixel region. A method of repairing the first data line comprises steps of: electrically connecting the first data line and the first pixel electrode within the first pixel region; electrically connecting the first pixel electrode and the second pixel electrode; and electrically connecting the second pixel electrode and the second broken point of the first data line within the second pixel region.
Accordingly, it is a major object of the invention to use laser fusing to form an electrical connection across the first pixel electrode and the second pixel electrode.
It is another object of the invention to repair the line defect on the substrate without fabricating extra wiring patterns on the peripheral region of the pixel region.
Yet another object of the invention is to prevent signal distortion caused by the repair line positioned across the adjacent data lines.
It is a further object of the invention to provide the electric connection vertically across more than two pixel electrodes if more than one opening is found on the same broken data line.
Still another object of the invention is to prevent the increase in RC delay time caused by resistance and capacitance of the repair line.
Another object of the invention is to provide an unlimited number of repair lines irrespective of the space and size of the flat display panel.
These and other objects of the present invention will become readily apparent upon further review of the following specification and drawings.